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I installed Ubuntu. Now I get:

"fatal err. not os detected.

I cant boot from dvd either

What can I do?

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marked as duplicate by Eric Carvalho, Braiam, guntbert, James Jan 2 '14 at 2:31

This question was marked as an exact duplicate of an existing question.

Is preboot right? You can't boot the DVD, nor USB, it's not a problem of grub. – Braiam Jan 1 '14 at 11:44

Without knowing exactly what you did I would guess you have broken your boot loader.

Look at this question and try the second method How can I repair grub? (How to get Ubuntu back after installing Windows?)

boot from live cd and run these commands

sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair
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